Dealing with Odour Nuisance in Rural Communities

Transcription

1 Dealing with Odour Nuisance in Rural Communities Qiang Zhang, PhD, PEng Professor Department of Biosystems Engineering University of Manitoba Manitoba, Canada

2 Presentation outline What is odour? Odour sources in rural community: agricultural (livestock) operations Regulations for odour management Odour impact assessment tool Key elements considered Interactive computer model

3 What is odour? Sensations that occur when a mixture of odourants (odour compounds) stimulate receptors in the nasal cavity. Odour is a complex psychophysical variable, not a simple physical or chemical variable.

4 Measuring odour Individual odour compounds may be measured with analytical instrument such as GC or GC/MS But there is no established correlation between the individual odour compounds and the human perception of odour The most reliable way of measuring odour is using the human olfactory sense (nose)

5 Odour attributes Concentration dilution to threshold: D/T detection threshold recognition threshold odour unit: OU or OU E Intensity: relative strength above threshold Persistence: rate of change of intensity with concentration Hedonic tone: (un)pleasantness

6 Odour attributes - concentration % of probability to be detected Dilution to detection: D/T = 6 or 6 OU (odour unit)

7 Dynamic-dilution olfactometer Sensory Panel 0.02 L/min 20 L/min flow control flow control odour filter D/T = = 1000 or 1000 UO/m 3 clean air

8 Olfactometer

9 Odour sources in rural communities Livestock operations production units: buildings or feedlots manure storage land application mortality disposal Other agricultural operations

10 Source: Purdue University

11 Regulations Mostly regulated under the nuisance provisions of common law. Consideration: prolonged, repeated and affect more than one person in the community. (Manitoba) Concentration-limit based 1 7 OU/m 3, mostly industry setting difficulty in measuring downwind odour Complaint based Setback distance

12 Setback requirements Empirical Experience Measurement Dispersion theory (science) based Some examples of setback model: MDS models in Ontario, Alberta OFFSET in Minnesota OFT in Nebraska

13 Odour dispersion in atmosphere Downwind: OU/m 3 Emission: OU/s

14 Key elements Emission Transportation Dispersion Setback distance =? Tolerance

15 Emission Operation and facility type Management Seasonal and time variations Mitigation technologies

16 Dispersion Physical dilution process Atmospheric conditions Topography Some issues Mean vs. peak Odour persistency Chemical reactions in atmosphere

17 Tolerance - complex frequency (refers to the number of times the odour is detected in a given time period); intensity (refers to the strength of the odour); duration (length of exposure); offensiveness (hedonic tone); receptor (physiological aspects of the person perceiving the odour).

18 Odour impact assessment tool (OIAT) Emission Dispersion modelling: Odour exposure Community odour acceptance level: % of population

19 Approach Emission model Based on measurements reported in the literature Size and type of operation, manure storage systems Dispersion modelling AERMOD Simulations based on historical weather data Community odour acceptance level Interview residents Developing correlation between the annoyance level and odour hours

20 Acceptability-Exposure Curve

21 Input screen

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24 Odour free frequency

25 Acceptability level

26 Odour acceptance map Level 1 Level 2 Level 3

27 Future expansion of OIAT Include other odour sources beyond hog operations Generate simple look-up charts to quickly estimate odour impact Web-based application?

28 ACKNOWLEDGEMENT Project Team Dr. Qiang Zhang, Biosystems Engineering, U of M Dr. Huiqing Guo, Chemical & Biological Engineering, U of S Zhu Gao, Ph.D. student, U of S Amy La, Ph.D. student, U of M Funding

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